A peptide chain release factor 2 affects the stability of UGA-containing transcripts in Arabidopsis chloroplasts
A peptide chain release factor 2 affects the stability of UGA-containing transcripts in Arabidopsis chloroplasts
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DOI：
10.1105/tpc.006809
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发表时间：
2002-12-01
期刊：
影响因子：
11.6
通讯作者：
Oelmüller, R
中科院分区：
文献类型：
--
作者：
Meurer, J;Lezhneva, L;Oelmüller, R
拟南芥中 hcf109（高叶绿素荧光）突变的定位克隆鉴定出一种核编码、质体定位的释放因子 2 样蛋白 AtprfB，表明叶绿体中的翻译终止过程与真细菌的翻译终止过程类似。光和组织对 atprfB 表达的控制与叶绿体发育有关。第二个内含子最后一个核苷酸的点突变导致下游出现一个新的剪接位点，从而导致 Hcf109 蛋白 N 末端区域的 7 个氨基酸残基缺失。该突变导致含有 UGA 的 mRNA 稳定性降低。我们的数据表明，具有 UGA 终止密码子的转录本仅由叶绿体中的 AtprfB 终止，并且 AtprfB 参与 mRNA 稳定性和蛋白质合成的调节。此外，序列数据显示蓝藻祖 prfB 基因的内部框内 TGA 终止密码子发生 +1 移码。 atprfB 的表达模式和功能可以反映仅在陆地植物质体基因组中保存 TGA 终止密码子的进化驱动力。
Positional cloning of the hcf109 (high chlorophyll fluorescence) mutation in Arabidopsis has identified a nucleus-encoded, plastid-localized release factor 2-like protein, AtprfB, indicating that the processes of translational termination in chloroplasts resemble those of eubacteria. Control of atprfB expression by light and tissues is connected to chloroplast development. A point mutation at the last nucleotide of the second intron causes a new splice site farther downstream, resulting in a deletion of seven amino acid residues in the N-terminal region of the Hcf109 protein. The mutation causes decreased stability of UGA-containing mRNAs. Our data suggest that transcripts with UGA stop codons are terminated exclusively by AtprfB in chloroplasts and that AtprfB is involved in the regulation of both mRNA stability and protein synthesis. Furthermore, sequence data reveal a +1 frameshift at an internal in-frame TGA stop codon in the progenitor prfB gene of cyanobacteria. The expression pattern and functions of atprfB could reflect evolutionary driving forces toward the conservation of TGA stop codons exclusively in plastid genomes of land plants.